Layered network organization is suitable for Broadband ISDN which support various traffic with a unique network interface. The layered network is constructed with very high speed WAN, high speed MAN and LAN. The purpose of this project is a development of layered organization technology for B-ISDN and concretely has three research themes as follows ; 1. High-speed transmission technology, 2. Interconnection and internetwork technology between different layers, 3. Traffic control technology. In the last year of this project, we settled the research purpose at the performance improvement of each network and the development of interconnection technology for different layered networks. The following shows the detail of the results of this year.1. We developed the network simulators for interconnection network system, interconnected very high-speed WAN and high-speed MAN. The simulator was used for the performance evaluation for network control schemes described below.2. We proposed a new r
… Moreouting scheme for broadcasting traffic. The scheme avoids the concentration of packet copy operation in intermediate switching nodes of tree shaped path which connects a source station and receiving stations.3. We proposed a new routing scheme for many kinds of traffic which requires different grade of service. This scheme uses different cost function for each traffic.4. We proposed a new access control scheme for ring networks, which introduces priority function to Resolvable Contention Ring scheme. Simulation results showed the scheme is suitable for multi-media environment because it can adjust the performance of each traffic by changing its priority parameter.5. We analyzed DQDB and suggested a major improvement taking care of fairness among stations.6. For the traffic control for interconnection networks, we proposed a new scheme for gateways which connect ATM networks and FDDI networks. The scheme is feedback type congestion control and is based on a FDDI transmission unit, a frame. The simulation results showed that the scheme leads no cell loss both inside an ATM network and at a receiving gateway. Less